Method for treating high-salinity wastewater by utilizing fungi

Abstract

The invention discloses a method for treating high-salinity wastewater by using fungi. The method comprises the following steps: preparing immobilized fungi by using a cotton thread carrier or a related carrier; arranging a bacterium-electricity coupling device; inoculating fungi in the high-salinity sterilized liquid culture medium, and applying different voltages through a direct-current power supply; treating the high-salinity wastewater by utilizing fungi under the regulation and control of a carbon source; the actual high-salinity wastewater is treated by utilizing electrical stimulation in cooperation with fungi. The method has remarkable environmental friendliness and economical efficiency, and compared with the prior art, the innovative treatment scheme has the advantages that generation of toxic substances is reduced, and use of chemical agents required by subsequent treatment is reduced. The method has the characteristics that the cost is low, the operation is simple and convenient, no extra chemical medicine is needed, and the harm to the environment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly relates to a method for treating high-salt wastewater by using fungi. Background Art

[0002] With the development of industry, the types of wastewater emissions are increasing day by day. Among them, high-salt wastewater is wastewater with a mass concentration of solid salt higher than 3.5%, mainly from industrial production, chemical engineering, and human life and other fields. If this wastewater is not properly treated, it will cause many environmental hazards. First of all, the discharge of high-salt wastewater will pollute the adjacent water bodies, endanger aquatic organisms, cause their death or loss, and the disappearance of these species will seriously affect the ecological environment. Secondly, high-salt wastewater will also exacerbate soil salinization and groundwater pollution, damage the foundation of agricultural production, and damage the growth and quality of crops. At the same time, treating high-salt wastewater can also realize the recycling of resources, which is of great significance. Therefore, high-salt wastewater must be treated.

[0003] With the increasingly strict discharge standards for high-salt wastewater, the treatment requirements for high-salt wastewater must reach "zero discharge". At present, the main treatment methods for high-salt wastewater consist of two aspects, namely desalination and removal of organic pollutants. The desalination method is to crystallize the salts in the wastewater by using the evaporation crystallization method, and then recycle or transport the crystallized salts for external treatment, and the condensed water is reused. If the salt substances can be recycled, it will greatly reduce the impact on the environment, so as to achieve the purpose of "zero discharge" of wastewater; the presence of pollutants will reduce the quality of the crystallized salts. Especially in the presence of toxic and harmful substances and heavy metals, the recycling value of the crystallized salts is reduced and they need to be disposed of as hazardous solid wastes. At present, the main treatment methods for organic pollutants in high-salt wastewater are biological treatment methods and physical and chemical treatment methods (adsorption method, coagulation sedimentation method, advanced oxidation method, etc.). However, a single method faces problems such as high energy consumption and limited treatment effect, and it is difficult to meet the discharge standards. Summary of the Invention

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide a method for treating high-salt wastewater by using fungi, which has the characteristics of low cost, simple operation, no need for additional chemical drugs, and reduction of harm to the environment. In order to achieve the above object and other advantages of the present invention, a method for treating high-salt wastewater by using fungi is provided, including:

[0005] A bacteria-electricity coupling device, the bacteria-electricity coupling device includes a container, high-salt wastewater placed in the container, an anode and a cathode placed in the high-salt wastewater, immobilized fungi placed in the high-salt wastewater, and a DC power supply electrically connected to the anode and the cathode;

[0006] Different voltages are applied to the high-salt wastewater through the DC power supply;

[0007] In the high-salt wastewater, the treatment of high-salt wastewater is carried out by using fungi through carbon source regulation and electrical stimulation, and then the electrical stimulation is combined with fungi to treat the actual high-salt wastewater.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: Fungi are used to treat high-salt wastewater with complex organic components. The fungi secrete a variety of specific enzymes, such as lignin peroxidase and laccase. These enzymes convert macromolecular organic substances into small molecules through oxidation-reduction reactions and finally mineralize them into carbon dioxide and water, effectively degrading the complex organic compounds in the high-salt wastewater. Under the condition of bacteria-electricity synergy, appropriate electrical stimulation improves the metabolic rate and level of the fungi, and still maintains the stability of the cell structure under nutrient-poor conditions, which helps the fungi to enter the secondary metabolic stage in advance, produce a variety of specific enzymes, have a higher degradation efficiency for aromatic ring substances, can significantly remove most metal ions in the sewage, and to a certain extent inhibit the generation of toxic compounds such as chlorobenzene and chlorophenol, reduce the toxicity of the high-salt wastewater, reduce the use of chemical agents in subsequent treatment, and reduce the subsequent treatment burden. Combining the experimental application of electrical stimulation and fungi will provide a more efficient and environmentally friendly solution for the treatment of high-salt wastewater and other industrial wastewaters with complex organic components. Description of the Drawings

[0009] Figure 1 Schematic diagram of the bacteria-electricity coupling technology experimental device for the method of treating high-salt wastewater with fungi according to the present invention;

[0010] Figure 2 Rate of glucose consumption by fungi in the culture medium at different voltages for the method of treating high-salt wastewater with fungi according to the present invention;

[0011] Figure 3 TOC change trend of the high-salt wastewater treated by fungi for the method of treating high-salt wastewater with fungi according to the present invention;

[0012] Figure 4 Removal rate of metal elements in the high-salt wastewater by fungi for the method of treating high-salt wastewater with fungi according to the present invention;

[0013] Figure 5 UV change trend of the high-salt wastewater treated by fungi for the method of treating high-salt wastewater with fungi according to the present invention; 254 Change trend;

[0014] Figure 6The variation of the treatment of organic matter in high-salt wastewater by fungi in the method for treating high-salt wastewater using fungi according to the present invention includes the use of parallel factor analysis to analyze the differences in each component. The fluorescence EEM spectrum is divided into five parts: Region I (Ex / Em = 200 - 250 nm / 280 - 330 nm), Region II (Ex / Em = 200 - 250 nm / 330 - 380 nm), Region III, Region IV (Ex / Em = 250 - 400 nm / 330 - 380 nm), and Region V (Ex / Em = 250 - 400 nm / 380 - 560 nm), which represent aromatic protein (AP I), aromatic protein (AP II), fulvic acid-like (FA), soluble microbial products (SMP), and humic acid-like (HA), respectively.

[0015] Figure 1 In the figure: 1. DC power supply; 2. Three-electrode electrolytic cell; 3. Anode; 4. Cathode; 5. Drain pipe; 6. High-salt wastewater; 7. Immobilized fungi. Specific embodiments

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Such as Figure 1 This is a schematic diagram of the experimental device of the present invention. This technology is based on the biodegradation technology of fungi, comprehensively using electrical stimulation to cooperate with fungi to degrade actual high-salt wastewater, enabling fungi to utilize their own metabolic activities to treat complex organic matter in high-salt wastewater under nutrient-poor conditions, achieving the effective removal of various complex organic matter in the wastewater and reducing the toxicity of the wastewater.

[0018] In the following embodiments of the present invention, the fungus selected is Trametes versicolor (CICC 14001) among white rot fungi, which is classified microbiologically as belonging to the family Polyporaceae and the genus Coriolus, and is purchased from the China Center for Industrial Culture Collection. The form of the obtained strain is a slant culture.

[0019] In the following embodiments of the present invention, the high-salt wastewater selected is petrochemical reverse osmosis concentrate, with a salinity of 3.90 ± 0.5% and the pH adjusted to 4.5 ± 0.5.

[0020] Example 1

[0021] A method for treating high-salt wastewater using fungi includes the following steps:

[0022] Fungi were inoculated in a sterilized Kirk medium with conductivity and salinity approximated to those of petrochemical reverse osmosis concentrate by adding NaCl. The approximated NaCl concentration was 0.25%, 200 ml for each medium. A voltage was applied through a DC power supply, with voltage gradients set at 0 V, 1 V, 2 V, 3 V, and 4 V. It was placed in a thermostatic shaker with parameters set at 28 °C and 150 rpm. The experimental period was 7 days. The glucose concentration in the medium was measured daily. The specific results are as Figure 2 shown.

[0023] As Figure 2 can be seen, in the gradient of 1 V - 3 V, the rate of glucose consumption by fungi increases with the increase of voltage. The voltage at which the consumption rate is the fastest is 3 V. At 4 V, although the glucose consumption rate is still faster than that at 0 V and 1 V, it is slower than that at 2 V and 3 V. In summary, 3 V is the optimal voltage for the growth of fungi in high-salt wastewater.

[0024] Example 2

[0025] A method for treating high-salt wastewater using fungi includes the following steps:

[0026] The cotton thread immobilized fungi were put into high-salt wastewater, and three carbon source regulation control groups were set up, namely, only adding fungi, not providing an initial carbon source and not supplementing the carbon source later; providing 0.5 g / L glucose as the initial carbon source and daily supplementing the concentrated solution of glucose and ammonium tartrate to supplement nutrient elements; only providing 0.5 g / L glucose as the initial carbon source and not continuing to supplement nutrients later, these three carbon source regulation methods. After completion, it was placed in a thermostatic shaker with parameters set at 28 °C and 150 rpm. The experimental period was 7 days, and the change of TOC in the sewage was measured. The specific results are as Figure 3 shown.

[0027] As Figure 3 can be seen, fungi have an obvious degradation trend for TOC. R0 reached the highest degradation rate on the 5th day, which was 34.96%. R1 and R2 reached the highest degradation rates on the 3rd day, which were 16.39% and 45.60% respectively. In comparison, the treatment effect of R2 was the best.

[0028] Example 3

[0029] A method for treating high-salt wastewater using fungi includes the following steps:

[0030] Under the conditions of carbon source regulation and electro-coupling with bacteria, the cotton thread immobilized fungi were respectively put into high-salt wastewater. The experimental period was set to 7 days. Inductively coupled plasma optical emission spectrometry was used to analyze the change of metal elements in the sewage. The specific results are as Figure 4 shown.

[0031] As Figure 4It can be seen that among the 32 metals measured, the fungus can achieve a certain removal effect on more than 60% of the metal elements. In the carbon source regulation group, the removal rates of Zn, Fe, and Zr can approach 90%, and under the action of bacteria-electric coupling, the removal rates of elements such as Cu, Mo, and Mg can reach between 80% and 90%.

[0032] Example 4

[0033] A method for treating high-salt wastewater using fungi includes the following steps:

[0034] Put the cotton thread-immobilized fungus into the high-salt wastewater and treat it using the bacteria-electric coupling technology. The experimental period is set to 7 days. Use an ultraviolet spectrophotometer to measure the removal effect of the fungus on UV 254 as follows. Figure 5 as shown.

[0035] It can be seen from Figure 5 that bacteria-electric coupling has an obvious removal effect on UV 254 in high-salt wastewater. The removal rate can reach 57.60% on the 3rd day. In the later stage, due to the metabolic action of the fungus, there are situations where some organic matters are regenerated or new organic matters are produced, resulting in a decrease in the removal rate. However, the removal rate can still reach 39.48% on the 7th day, which is higher than the removal rate of only electrochemical treatment. This indicates that the fungus can gradually adsorb and degrade humus-like substances and aromatic compounds containing C = C double bonds and C = O double bonds in the sewage.

[0036] Example 5

[0037] A method for treating high-salt wastewater using fungi includes the following steps:

[0038] Put the cotton thread-immobilized fungus into the high-salt wastewater and treat it using the bacteria-electric coupling technology. The experimental period is set to 5 days. Use 3D-EEM to describe the changes in organic matters in high-salt wastewater on the 15th day. The specific results are as Figure 5 shown.

[0039] It can be seen from Figure 6 that when bacteria-electric coupling occurs, significant changes in regions III and V can be found on the 1st day. The removal rates of fulvic acid-like substances and humic acid substances reach 92% and 79% respectively. After the 5th day, the removal rates are still increased by 3% and 9% respectively. The removal rate of aromatic protein I is only 13% on the 1st day, but the removal rate of aromatic protein II reaches 50%. Moreover, 38% of the soluble microbial products are also removed.

[0040] In summary, the present invention discovers that electrical stimulation can effectively assist fungi in surviving in a high-salt environment and delaying the aging rate of fungi in high-salt wastewater, which helps to improve the degradation efficiency of fungi, promote resource recovery and enhance treatment stability, providing an effective treatment method for high-salt sewage treatment. With the help of electrical stimulation, fungi effectively remove aromatic protein II, as well as fulvic acid, humic acid substances, aromatic ring substances and soluble microbial products in high-salt wastewater, reducing the burden in the subsequent sewage treatment process, decreasing the use of chemical agents and treatment time, and thus reducing the overall treatment cost. Fungi can effectively inhibit the generation of toxic compounds in high-salt wastewater and have an obvious degradation effect on pharmaceutical active compounds, thereby reducing the impact on water bodies and the ecosystem and protecting aquatic organisms and ecological balance. During the degradation process, fungi can release nutrients such as nitrogen and phosphorus, which can be used for subsequent agricultural fertilization or water treatment to promote the recycling of resources.

[0041] The equipment quantity and treatment scale described here are used to simplify the description of the present invention, and the application, modification and variation of the present invention are obvious to those skilled in the art.

[0042] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the illustrated and described examples here.

Claims

1. A method for treating high-salinity wastewater using fungi, characterized in that: include: A bacteria-electric coupling device, the bacteria-electric coupling device comprising a container, high-salinity wastewater placed in the container, an anode and a cathode placed in the high-salinity wastewater, immobilized fungi placed in the high-salinity wastewater, and a direct current power supply electrically connected to the anode and the cathode; Applying different voltages to the high-salinity wastewater through the DC power supply; The high-salinity wastewater is treated by fungi through carbon source regulation and electrical stimulation, thereby achieving electrical stimulation and fungi synergistically treating actual high-salinity wastewater.

2. A method for treating high-salinity wastewater using fungi as claimed in claim 1, characterized in that: The fungus is selected from one or a combination of white rot fungi such as Trametes versicolor and Phanerochaete chrysosporium or Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Aspergillus polymorpha and the like.

3. A method for treating high-salinity wastewater using fungi as claimed in claim 1, characterized in that: The immobilized fungi were specifically prepared as follows: Add the prepared mycelium suspension into the cooled Kirk liquid culture medium, ensure uniform dispersion, add the trimmed cotton thread carrier and mix with the suspension. After completion, place the culture bottle in a constant temperature shaker for 5-7 days, and set the parameters to 28℃, 150rpm.

4. The method for treating high-salinity wastewater using fungi according to claim 1, characterized in that: The bacteria-electricity coupling device uses an ordinary three-hole three-electrode electrolytic cell as a liquid reaction container, applies voltage through a DC power supply, the electrode size is 200*250mm, and the electrode spacing is 20mm; the material of the anode is any one or more alloys of zinc, aluminum, iridium, nickel, titanium, and copper; the material of the cathode is any one or more alloys of platinum, copper, bismuth, and iron, or a carbon material.

5. The method for treating high-salinity wastewater using fungi according to claim 1, characterized in that: The fungus is inoculated in a high-salinity sterilized liquid culture medium, specifically by adding NaCl to increase the conductivity and salinity of the Kirk liquid culture medium. After the fungus is inoculated, a voltage is applied through a DC power supply, a voltage gradient is set, and the culture is carried out for 7 days.

6. The method for treating high-salinity wastewater using fungi as claimed in claim 1, characterized in that: Before using the bacteria-electricity coupling device, aeration was performed near the cathode in the bacteria-electricity coupling device for 10 minutes with a gas flow rate of 0.6 L / min, and no aeration was provided later.

7. The method for treating high-salinity wastewater using fungi as claimed in claim 1, characterized in that: The fungus immobilization carrier material used in the experiment is one or a combination of polyester fiber, cotton thread, polypropylene fiber, nylon mesh, copper wire, titanium wire, and aluminum wire.

8. The method for treating high-salinity wastewater using fungi as claimed in claim 1, characterized in that: The fungus biologically treats actual high-salinity wastewater. The dosage of immobilized fungi in the experiment is 1-10 DCW / L, and the experimental period is 4-10 days. The salinity range of the actual high-salinity wastewater is 3-6 g / L, and the initial pH is 6-9.

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